PATH variable management in Linux CLI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to display the current PATH variable.

Linux CLI

echo $[1]

Drag options to blanks, or click blank then click option'

APATH

BHOME

CUSER

DPWD

Attempts:

3 left

💡 Hint

Common Mistakes

Using $HOME or $USER instead of $PATH.

Forgetting the $ sign before the variable name.

The PATH variable holds directories where the system looks for executables. Using echo $PATH shows its current value.

2fill in blank

medium

Complete the code to add the directory /usr/local/bin to the PATH variable temporarily.

Linux CLI

export PATH=[1]:/usr/local/bin

Drag options to blanks, or click blank then click option'

A/usr/bin

B$PATH

C$HOME

DPATH

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting the $ sign before PATH.

Replacing PATH instead of appending to it.

To add a directory to PATH, prepend or append it to the existing $PATH variable using export PATH=$PATH:/new/dir.

3fill in blank

hard

Fix the error in the code that tries to add /opt/bin to PATH but overwrites it.

Linux CLI

export PATH=[1]:/opt/bin

Drag options to blanks, or click blank then click option'

A$HOME

BPATH

C$PATH

D/opt/bin

Attempts:

3 left

💡 Hint

Common Mistakes

Writing PATH without $ causing the variable to be overwritten.

Using unrelated variables like $HOME.

Using PATH without $ treats it as a string, not the variable's value. Use $PATH to get the current PATH contents.

4fill in blank

hard

Fill both blanks to permanently add /custom/bin to PATH in the .bashrc file.

Linux CLI

echo 'export PATH=[1]:[2]' >> ~/.bashrc

Drag options to blanks, or click blank then click option'

A$PATH

B/custom/bin

C$HOME

D/usr/local/bin

Attempts:

3 left

💡 Hint

Common Mistakes

Overwriting PATH by not including $PATH.

Adding wrong directory paths.

To add a directory permanently, append export PATH=$PATH:/custom/bin to ~/.bashrc. This keeps existing PATH and adds the new directory.

5fill in blank

hard

Fill all three blanks to create a script that adds /my/bin to PATH only if it's not already included.

Linux CLI

if [[ ":$[1]:" != *":[2]:"* ]]; then
  export PATH=[3]:/my/bin
fi

Drag options to blanks, or click blank then click option'

APATH

B/my/bin

C$PATH

D/usr/bin

Attempts:

3 left

💡 Hint

Common Mistakes

Not using colons around PATH for accurate matching.

Using PATH without $ to get its value.

Appending instead of prepending PATH.

This script checks if /my/bin is in $PATH. If not, it prepends it. The syntax uses [[ ":$PATH:" != *":/my/bin:"* ]] for safe matching.

Practice

1. What does the PATH environment variable do in Linux?

easy

A. It lists folders where the system looks for commands to run.

B. It stores the current user's password.

C. It shows the current directory path.

D. It controls the screen brightness settings.

Solution

1. Step 1: Understand the role of PATH

   The PATH variable contains directories where the system searches for executable commands.

2. Step 2: Match the description to the options

   Only It lists folders where the system looks for commands to run. correctly describes PATH as a list of folders for commands.

3. Final Answer:

   It lists folders where the system looks for commands to run. -> Option A

4. Quick Check:

   PATH = command search folders [OK]

Hint: PATH is where your system finds commands to run [OK]

Common Mistakes:

• Confusing PATH with current directory
• Thinking PATH stores passwords
• Assuming PATH controls hardware settings

2. Which of the following is the correct syntax to add /home/user/bin at the start of your PATH variable in a bash shell?

easy

A. set PATH=/home/user/bin:$PATH

B. export PATH=$PATH:/home/user/bin

C. export PATH=/home/user/bin:$PATH

D. PATH=/home/user/bin:$PATH export

Solution

1. Step 1: Recall how to prepend a folder to PATH

   To add a folder at the start, use export PATH=folder:$PATH.

2. Step 2: Check each option's syntax

   export PATH=/home/user/bin:$PATH correctly uses export PATH=/home/user/bin:$PATH. export PATH=$PATH:/home/user/bin appends instead of prepends. set PATH=/home/user/bin:$PATH uses wrong command 'set'. PATH=/home/user/bin:$PATH export has wrong order.

3. Final Answer:

   export PATH=/home/user/bin:$PATH -> Option C

4. Quick Check:

   Prepend folder with export PATH=folder:$PATH [OK]

Hint: Use export PATH=folder:$PATH to add at start [OK]

Common Mistakes:

• Appending instead of prepending
• Using 'set' instead of 'export'
• Incorrect command order

3. Given the commands run in order:
export PATH=/usr/local/bin:$PATH
export PATH=$PATH:/home/user/scripts
What is the resulting PATH if the original PATH was /usr/bin:/bin?

medium

A. /usr/local/bin:/home/user/scripts:/usr/bin:/bin

B. /home/user/scripts:/usr/local/bin:/usr/bin:/bin

C. /usr/bin:/bin:/usr/local/bin:/home/user/scripts

D. /usr/local/bin:/usr/bin:/bin:/home/user/scripts

Solution

1. Step 1: Apply first export command

   Original PATH: /usr/bin:/bin
   After export PATH=/usr/local/bin:$PATH, PATH becomes /usr/local/bin:/usr/bin:/bin.

2. Step 2: Apply second export command

   Now export PATH=$PATH:/home/user/scripts appends /home/user/scripts.
   Final PATH: /usr/local/bin:/usr/bin:/bin:/home/user/scripts.

3. Final Answer:

   /usr/local/bin:/usr/bin:/bin:/home/user/scripts -> Option D

4. Quick Check:

   Prepend then append folder to PATH [OK]

Hint: Apply exports in order, watch prepend vs append [OK]

Common Mistakes:

• Mixing order of folders
• Forgetting original PATH
• Confusing prepend and append

4. You want to add /opt/tools to your PATH, but after running export PATH=$PATH:/opt/tools, your scripts in /opt/tools still don't run. What is the likely problem?

medium

A. You forgot to reload the shell or source the profile

B. /opt/tools is not executable

C. You should prepend, not append, the folder

D. PATH variable cannot be changed

Solution

1. Step 1: Understand PATH changes need shell reload

   Changing PATH in a shell session affects only that session. To use changes in new sessions, reload or source profile.

2. Step 2: Check other options

   /opt/tools being non-executable is unlikely for a folder. Prepend vs append doesn't prevent running scripts if PATH is correct. PATH can be changed.

3. Final Answer:

   You forgot to reload the shell or source the profile -> Option A

4. Quick Check:

   Reload shell to apply PATH changes [OK]

Hint: Reload shell or source profile after PATH change [OK]

Common Mistakes:

• Not reloading shell after export
• Confusing folder permissions with executables
• Thinking PATH is immutable

5. You want to add /custom/bin to your PATH only for your current terminal session without affecting others. Which command should you use?

hard

A. set PATH=/custom/bin:$PATH

B. export PATH=/custom/bin:$PATH

C. sudo export PATH=/custom/bin:$PATH

D. echo '/custom/bin' >> ~/.bashrc

Solution

1. Step 1: Identify session-only PATH change

   Using export PATH=/custom/bin:$PATH changes PATH only in current shell session.

2. Step 2: Evaluate other options

   echo '/custom/bin' >> ~/.bashrc appends to .bashrc, affecting future sessions, not current only. sudo export PATH=/custom/bin:$PATH uses sudo unnecessarily and is invalid syntax. set PATH=/custom/bin:$PATH uses wrong command 'set'.

3. Final Answer:

   export PATH=/custom/bin:$PATH -> Option B

4. Quick Check:

   Use export for session-only PATH change [OK]

Hint: Use export to change PATH only in current session [OK]

Common Mistakes:

• Editing .bashrc for immediate effect
• Using sudo with export
• Using wrong commands like set